Method and arrangement for separation of CO
View Patent ↗A method for separating CO 2 from combustion exhaust gas includes discharging the CO 2 -containing combustion exhaust gas mass flow into the carbonator of a carbonate looping system having at least one carbonator and one calciner. Combining the CO 2 of the combustion exhaust gas mass flow with a carbonate-forming sorbent inside the carbonator to form a carbonate. Sending the carbonate as a carbonate-solids mass flow is sent to the calciner. Burning the carbonate at the carbonate-specific calcination temperature by the addition of heat provided by an additional firing that uses oxygen as the oxidant, whereby regenerated sorbent and a gas essentially containing CO 2 is formed. Sending the hot regenerated sorbent to the carbonator as a sorbent-solids mass flow for carbonization of CO 2 , and discharging the hot gas as gas mass flow. Replacing at least a portion of the heat of the additional firing with heat removed from the carbonate-solids mass flow or the gas mass flow in one or more heat exchangers prior to its entry into the calciner or inside the calciner.
1. An improved method for separating CO 2 from combustion exhaust gas produced in a furnace through the combustion of carbon based fuels or wastes with air as an oxidizing agent, the method comprising the following steps:
discharging the CO 2 -containing combustion exhaust gas mass flow from the furnace into a carbonator of a carbonate looping system, the carbonate looping system including at least one carbonator and at least one calciner and having a carbonate-forming sorbent flowing within the loop;
combining the sorbent with the CO 2 of the combustion exhaust gas mass flow within the carbonator to form a carbonate;
sending the carbonate as a carbonate-solids mass flow to the calciner;
burning the carbonate in the calciner at a carbonate-specific calcination temperature by adding heat produced by an additional firing that uses oxygen as the oxidant, whereby a regenerated sorbent and a gas substantially containing CO 2 are formed;
sending the hot regenerated sorbent to the carbonator as a sorbent-solids mass flow for carbonization of CO 2 ; and
sending the hot gas as a gas mass flow for further treatment;
wherein the improvement comprises replacing at least a portion of the additional firing with heat that is removed from one or more heat sources and is sent through indirect heat exchange to the carbonate-solids mass flow before the carbonate-solids mass flow enters the calciner; and
wherein the sorbent-solids mass flow is used as a heat source and the removal of a part of its contained heat by the carbonate-solids mass flow takes place in a heat exchanger prior to the entry of the sorbent-solids mass flow into the carbonator, the heat exchanger physically separating the carbonate-solids mass flow from the sorbent-solids mass flow.
2. The method of claim 1 , wherein the gas mass flow leaving at a separator downstream of the calciner is used as a heat source, and the removal of a part of its contained heat takes place prior to a further treatment.
3. The method of claim 1 , wherein an external heat source that has a higher temperature than the operating temperature inside the carbonator is utilized as a heat source, and the removal of at least a part of the contained heat of this external heat source takes place.
4. The method of claim 1 , wherein natural or synthetic materials are used as the sorbent.
5. The method of claim 1 , wherein CaO is used as an absorption agent.
6. The method of claim 1 , wherein the heat exchange takes place regeneratively or recuperatively.
7. The method of claim 1 , wherein fossil fuels or biomass or wastes or a mixture of the substances mentioned above are used for the additional firing in the calciner.
8. The method of claim 1 , wherein the heat transfer takes place by means of a heat transfer medium that exhibits favorable thermodynamic properties.
9. The method of claim 8 , wherein helium or sodium is used as the heat transfer medium.